package android.opengl;

import java.io.Writer;
import java.util.ArrayList;

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGL11;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.egl.EGLSurface;
import javax.microedition.khronos.opengles.GL;
import javax.microedition.khronos.opengles.GL10;

import android.opengl.BaseConfigChooser.ComponentSizeChooser;
import android.opengl.BaseConfigChooser.SimpleEGLConfigChooser;
import android.service.wallpaper.WallpaperService;
import android.util.Log;
import android.view.SurfaceHolder;

public class GLWallpaperService extends WallpaperService {
private static final String TAG = "GLWallpaperService";

@Override
public Engine onCreateEngine() {
return new GLEngine();
}

public class GLEngine extends Engine {
public final static int RENDERMODE_WHEN_DIRTY = 0;
public final static int RENDERMODE_CONTINUOUSLY = 1;

private GLThread mGLThread;
private EGLConfigChooser mEGLConfigChooser;
private EGLContextFactory mEGLContextFactory;
private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
private GLWrapper mGLWrapper;
private int mDebugFlags;

public GLEngine() {
super();
}

@Override
public void onVisibilityChanged(boolean visible) {
if (visible) {
onResume();
} else {
onPause();
}
super.onVisibilityChanged(visible);
}

@Override
public void onCreate(SurfaceHolder surfaceHolder) {
super.onCreate(surfaceHolder);
// Log.d(TAG, "GLEngine.onCreate()");
}

@Override
public void onDestroy() {
super.onDestroy();
// Log.d(TAG, "GLEngine.onDestroy()");
mGLThread.requestExitAndWait();
}

@Override
public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// Log.d(TAG, "onSurfaceChanged()");
mGLThread.onWindowResize(width, height);
super.onSurfaceChanged(holder, format, width, height);
}

@Override
public void onSurfaceCreated(SurfaceHolder holder) {
Log.d(TAG, "onSurfaceCreated()");
mGLThread.surfaceCreated(holder);
super.onSurfaceCreated(holder);
}

@Override
public void onSurfaceDestroyed(SurfaceHolder holder) {
Log.d(TAG, "onSurfaceDestroyed()");
mGLThread.surfaceDestroyed();
super.onSurfaceDestroyed(holder);
}

/**
* An EGL helper class.
*/
public void setGLWrapper(GLWrapper glWrapper) {
mGLWrapper = glWrapper;
}

public void setDebugFlags(int debugFlags) {
mDebugFlags = debugFlags;
}

public int getDebugFlags() {
return mDebugFlags;
}

public void setRenderer(Renderer renderer) {
checkRenderThreadState();
if (mEGLConfigChooser == null) {
mEGLConfigChooser = new SimpleEGLConfigChooser(true);
}
if (mEGLContextFactory == null) {
mEGLContextFactory = new DefaultContextFactory();
}
if (mEGLWindowSurfaceFactory == null) {
mEGLWindowSurfaceFactory = new DefaultWindowSurfaceFactory();
}
mGLThread = new GLThread(renderer, mEGLConfigChooser, mEGLContextFactory, mEGLWindowSurfaceFactory, mGLWrapper);
mGLThread.start();
}

public void setEGLContextFactory(EGLContextFactory factory) {
checkRenderThreadState();
mEGLContextFactory = factory;
}

public void setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory factory) {
checkRenderThreadState();
mEGLWindowSurfaceFactory = factory;
}

public void setEGLConfigChooser(EGLConfigChooser configChooser) {
checkRenderThreadState();
mEGLConfigChooser = configChooser;
}

public void setEGLConfigChooser(boolean needDepth) {
setEGLConfigChooser(new SimpleEGLConfigChooser(needDepth));
}

public void setEGLConfigChooser(int redSize, int greenSize, int blueSize, int alphaSize, int depthSize,
int stencilSize) {
setEGLConfigChooser(new ComponentSizeChooser(redSize, greenSize, blueSize, alphaSize, depthSize,
stencilSize));
}

public void setRenderMode(int renderMode) {
mGLThread.setRenderMode(renderMode);
}

public int getRenderMode() {
return mGLThread.getRenderMode();
}

public void requestRender() {
mGLThread.requestRender();
}

public void onPause() {
mGLThread.onPause();
}

public void onResume() {
mGLThread.onResume();
}

public void queueEvent(Runnable r) {
mGLThread.queueEvent(r);
}

private void checkRenderThreadState() {
if (mGLThread != null) {
throw new IllegalStateException("setRenderer has already been called for this instance.");
}
}
}

public interface Renderer {

public void onSurfaceCreated(GL10 gl, EGLConfig config);

public void onSurfaceChanged(GL10 gl, int width, int height);

public void onDrawFrame(GL10 gl);
}
}

class LogWriter extends Writer {
private StringBuilder mBuilder = new StringBuilder();

@Override
public void close() {
flushBuilder();
}

@Override
public void flush() {
flushBuilder();
}

@Override
public void write(char[] buf, int offset, int count) {
for (int i = 0; i < count; i++) {
char c = buf[offset + i];
if (c == '\n') {
flushBuilder();
} else {
mBuilder.append(c);
}
}
}

private void flushBuilder() {
if (mBuilder.length() > 0) {
Log.v("GLSurfaceView", mBuilder.toString());
mBuilder.delete(0, mBuilder.length());
}
}
}

// ----------------------------------------------------------------------

/**
* An interface for customizing the eglCreateContext and eglDestroyContext calls.
*

* This interface must be implemented by clients wishing to call
* {@link GLWallpaperService#setEGLContextFactory(EGLContextFactory)}
*/
interface EGLContextFactory {
EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig);

void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context);
}

class DefaultContextFactory implements EGLContextFactory {

public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig config) {
return egl.eglCreateContext(display, config, EGL10.EGL_NO_CONTEXT, null);
}

public void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context) {
egl.eglDestroyContext(display, context);
}
}

/**
* An interface for customizing the eglCreateWindowSurface and eglDestroySurface calls.
*

* This interface must be implemented by clients wishing to call
* {@link GLWallpaperService#setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory)}
*/
interface EGLWindowSurfaceFactory {
EGLSurface createWindowSurface(EGL10 egl, EGLDisplay display, EGLConfig config, Object nativeWindow);

void destroySurface(EGL10 egl, EGLDisplay display, EGLSurface surface);
}

class DefaultWindowSurfaceFactory implements EGLWindowSurfaceFactory {

public EGLSurface createWindowSurface(EGL10 egl, EGLDisplay
display, EGLConfig config, Object nativeWindow) {
// this is a bit of a hack to work around Droid init problems - if you don't have this, it'll get hung up on orientation changes
EGLSurface eglSurface = null;
while (eglSurface == null) {
try {
eglSurface = egl.eglCreateWindowSurface(display,
config, nativeWindow, null);
} catch (Throwable t) {
} finally {
if (eglSurface == null) {
try {
Thread.sleep(10);
} catch (InterruptedException t) {
}
}
}
}
return eglSurface;
}

public void destroySurface(EGL10 egl, EGLDisplay display, EGLSurface surface) {
egl.eglDestroySurface(display, surface);
}
}

interface GLWrapper {
/**
* Wraps a gl interface in another gl interface.
*
* @param gl
* a GL interface that is to be wrapped.
* @return either the input argument or another GL object that wraps the input argument.
*/
GL wrap(GL gl);
}

class EglHelper {

private EGL10 mEgl;
private EGLDisplay mEglDisplay;
private EGLSurface mEglSurface;
private EGLContext mEglContext;
EGLConfig mEglConfig;

private EGLConfigChooser mEGLConfigChooser;
private EGLContextFactory mEGLContextFactory;
private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
private GLWrapper mGLWrapper;

public EglHelper(EGLConfigChooser chooser, EGLContextFactory contextFactory,
EGLWindowSurfaceFactory surfaceFactory, GLWrapper wrapper) {
this.mEGLConfigChooser = chooser;
this.mEGLContextFactory = contextFactory;
this.mEGLWindowSurfaceFactory = surfaceFactory;
this.mGLWrapper = wrapper;
}

/**
* Initialize EGL for a given configuration spec.
*
* @param configSpec
*/
public void start() {
Log.d("EglHelper" + instanceId, "start()");
if (mEgl == null) {
Log.d("EglHelper" + instanceId, "getting new EGL");
/*
* Get an EGL instance
*/
mEgl = (EGL10) EGLContext.getEGL();
} else {
Log.d("EglHelper" + instanceId, "reusing EGL");
}

if (mEglDisplay == null) {
Log.d("EglHelper" + instanceId, "getting new display");
/*
* Get to the default display.
*/
mEglDisplay = mEgl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
} else {
Log.d("EglHelper" + instanceId, "reusing display");
}

if (mEglConfig == null) {
Log.d("EglHelper" + instanceId, "getting new config");
/*
* We can now initialize EGL for that display
*/
int[] version = new int[2];
mEgl.eglInitialize(mEglDisplay, version);
mEglConfig = mEGLConfigChooser.chooseConfig(mEgl, mEglDisplay);
} else {
Log.d("EglHelper" + instanceId, "reusing config");
}

if (mEglContext == null) {
Log.d("EglHelper" + instanceId, "creating new context");
/*
* Create an OpenGL ES context. This must be done only once, an OpenGL context is a somewhat heavy object.
*/
mEglContext = mEGLContextFactory.createContext(mEgl, mEglDisplay, mEglConfig);
if (mEglContext == null || mEglContext == EGL10.EGL_NO_CONTEXT) {
throw new RuntimeException("createContext failed");
}
} else {
Log.d("EglHelper" + instanceId, "reusing context");
}

mEglSurface = null;
}

/*
* React to the creation of a new surface by creating and returning an OpenGL interface that renders to that
* surface.
*/
public GL createSurface(SurfaceHolder holder) {
/*
* The window size has changed, so we need to create a new surface.
*/
if (mEglSurface != null && mEglSurface != EGL10.EGL_NO_SURFACE) {

/*
* Unbind and destroy the old EGL surface, if there is one.
*/
mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_CONTEXT);
mEGLWindowSurfaceFactory.destroySurface(mEgl, mEglDisplay, mEglSurface);
}

/*
* Create an EGL surface we can render into.
*/
mEglSurface = mEGLWindowSurfaceFactory.createWindowSurface(mEgl, mEglDisplay, mEglConfig, holder);

if (mEglSurface == null || mEglSurface == EGL10.EGL_NO_SURFACE) {
throw new RuntimeException("createWindowSurface failed");
}

/*
* Before we can issue GL commands, we need to make sure the context is current and bound to a surface.
*/
if (!mEgl.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext)) {
throw new RuntimeException("eglMakeCurrent failed.");
}

GL gl = mEglContext.getGL();
if (mGLWrapper != null) {
gl = mGLWrapper.wrap(gl);
}

/*
* if ((mDebugFlags & (DEBUG_CHECK_GL_ERROR | DEBUG_LOG_GL_CALLS))!= 0) { int configFlags = 0; Writer log =
* null; if ((mDebugFlags & DEBUG_CHECK_GL_ERROR) != 0) { configFlags |= GLDebugHelper.CONFIG_CHECK_GL_ERROR; }
* if ((mDebugFlags & DEBUG_LOG_GL_CALLS) != 0) { log = new LogWriter(); } gl = GLDebugHelper.wrap(gl,
* configFlags, log); }
*/
return gl;
}

/**
* Display the current render surface.
*
* @return false if the context has been lost.
*/
public boolean swap() {
mEgl.eglSwapBuffers(mEglDisplay, mEglSurface);

/*
* Always check for EGL_CONTEXT_LOST, which means the context and all associated data were lost (For instance
* because the device went to sleep). We need to sleep until we get a new surface.
*/
return mEgl.eglGetError() != EGL11.EGL_CONTEXT_LOST;
}

public void destroySurface() {
if (mEglSurface != null && mEglSurface != EGL10.EGL_NO_SURFACE) {
mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_CONTEXT);
mEGLWindowSurfaceFactory.destroySurface(mEgl, mEglDisplay, mEglSurface);
mEglSurface = null;
}
}

public void finish() {
if (mEglContext != null) {
mEGLContextFactory.destroyContext(mEgl, mEglDisplay, mEglContext);
mEglContext = null;
}
if (mEglDisplay != null) {
mEgl.eglTerminate(mEglDisplay);
mEglDisplay = null;
}
}
}

class GLThread extends Thread {
private final static boolean LOG_THREADS = false;
public final static int DEBUG_CHECK_GL_ERROR = 1;
public final static int DEBUG_LOG_GL_CALLS = 2;

private final GLThreadManager sGLThreadManager = new GLThreadManager();
private GLThread mEglOwner;

private EGLConfigChooser mEGLConfigChooser;
private EGLContextFactory mEGLContextFactory;
private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
private GLWrapper mGLWrapper;

public SurfaceHolder mHolder;
private boolean mSizeChanged = true;

// Once the thread is started, all accesses to the following member
// variables are protected by the sGLThreadManager monitor
public boolean mDone;
private boolean mPaused;
private boolean mHasSurface;
private boolean mWaitingForSurface;
private boolean mHaveEgl;
private int mWidth;
private int mHeight;
private int mRenderMode;
private boolean mRequestRender;
private boolean mEventsWaiting;
// End of member variables protected by the sGLThreadManager monitor.

private GLWallpaperService.Renderer mRenderer;
private ArrayList mEventQueue = new ArrayList();
private EglHelper mEglHelper;

GLThread(GLWallpaperService.Renderer renderer, EGLConfigChooser chooser, EGLContextFactory contextFactory,
EGLWindowSurfaceFactory surfaceFactory, GLWrapper wrapper) {
super();
mDone = false;
mWidth = 0;
mHeight = 0;
mRequestRender = true;
mRenderMode = GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY;
mRenderer = renderer;
this.mEGLConfigChooser = chooser;
this.mEGLContextFactory = contextFactory;
this.mEGLWindowSurfaceFactory = surfaceFactory;
this.mGLWrapper = wrapper;
}

@Override
public void run() {
setName("GLThread " + getId());
if (LOG_THREADS) {
Log.i("GLThread", "starting tid=" + getId());
}

try {
guardedRun();
} catch (InterruptedException e) {
// fall thru and exit normally
} finally {
sGLThreadManager.threadExiting(this);
}
}

/*
* This private method should only be called inside a synchronized(sGLThreadManager) block.
*/
private void stopEglLocked() {
if (mHaveEgl) {
mHaveEgl = false;
mEglHelper.destroySurface();
sGLThreadManager.releaseEglSurface(this);
}
}

private void guardedRun() throws InterruptedException {
mEglHelper = new EglHelper(mEGLConfigChooser, mEGLContextFactory, mEGLWindowSurfaceFactory, mGLWrapper);
try {
GL10 gl = null;
boolean tellRendererSurfaceCreated = true;
boolean tellRendererSurfaceChanged = true;

/*
* This is our main activity thread's loop, we go until asked to quit.
*/
while (!isDone()) {
/*
* Update the asynchronous state (window size)
*/
int w = 0;
int h = 0;
boolean changed = false;
boolean needStart = false;
boolean eventsWaiting = false;

synchronized (sGLThreadManager) {
while (true) {
// Manage acquiring and releasing the SurfaceView
// surface and the EGL surface.
if (mPaused) {
stopEglLocked();
}
if (!mHasSurface) {
if (!mWaitingForSurface) {
stopEglLocked();
mWaitingForSurface = true;
sGLThreadManager.notifyAll();
}
} else {
if (!mHaveEgl) {
if (sGLThreadManager.tryAcquireEglSurface(this)) {
mHaveEgl = true;
mEglHelper.start();
mRequestRender = true;
needStart = true;
}
}
}

// Check if we need to wait. If not, update any state
// that needs to be updated, copy any state that
// needs to be copied, and use "break" to exit the
// wait loop.

if (mDone) {
return;
}

if (mEventsWaiting) {
eventsWaiting = true;
mEventsWaiting = false;
break;
}

if ((!mPaused) && mHasSurface && mHaveEgl && (mWidth > 0) && (mHeight > 0)
&& (mRequestRender || (mRenderMode == GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY))) {
changed = mSizeChanged;
w = mWidth;
h = mHeight;
mSizeChanged = false;
mRequestRender = false;
if (mHasSurface && mWaitingForSurface) {
changed = true;
mWaitingForSurface = false;
sGLThreadManager.notifyAll();
}
break;
}

// By design, this is the only place where we wait().

if (LOG_THREADS) {
Log.i("GLThread", "waiting tid=" + getId());
}
sGLThreadManager.wait();
}
} // end of synchronized(sGLThreadManager)

/*
* Handle queued events
*/
if (eventsWaiting) {
Runnable r;
while ((r = getEvent()) != null) {
r.run();
if (isDone()) {
return;
}
}
// Go back and see if we need to wait to render.
continue;
}

if (needStart) {
tellRendererSurfaceCreated = true;
changed = true;
}
if (changed) {
gl = (GL10) mEglHelper.createSurface(mHolder);
tellRendererSurfaceChanged = true;
}
if (tellRendererSurfaceCreated) {
mRenderer.onSurfaceCreated(gl, mEglHelper.mEglConfig);
tellRendererSurfaceCreated = false;
}
if (tellRendererSurfaceChanged) {
mRenderer.onSurfaceChanged(gl, w, h);
tellRendererSurfaceChanged = false;
}
if ((w > 0) && (h > 0)) {
/* draw a frame here */
mRenderer.onDrawFrame(gl);

/*
* Once we're done with GL, we need to call swapBuffers() to instruct the system to display the
* rendered frame
*/
mEglHelper.swap();
}
}
} finally {
/*
* clean-up everything...
*/
synchronized (sGLThreadManager) {
stopEglLocked();
mEglHelper.finish();
}
}
}

private boolean isDone() {
synchronized (sGLThreadManager) {
return mDone;
}
}

public void setRenderMode(int renderMode) {
if (!((GLWallpaperService.GLEngine.RENDERMODE_WHEN_DIRTY <= renderMode) && (renderMode <= GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY))) {
throw new IllegalArgumentException("renderMode");
}
synchronized (sGLThreadManager) {
mRenderMode = renderMode;
if (renderMode == GLWallpaperService.GLEngine.RENDERMODE_CONTINUOUSLY) {
sGLThreadManager.notifyAll();
}
}
}

public int getRenderMode() {
synchronized (sGLThreadManager) {
return mRenderMode;
}
}

public void requestRender() {
synchronized (sGLThreadManager) {
mRequestRender = true;
sGLThreadManager.notifyAll();
}
}

public void surfaceCreated(SurfaceHolder holder) {
mHolder = holder;
synchronized (sGLThreadManager) {
if (LOG_THREADS) {
Log.i("GLThread", "surfaceCreated tid=" + getId());
}
mHasSurface = true;
sGLThreadManager.notifyAll();
}
}

public void surfaceDestroyed() {
synchronized (sGLThreadManager) {
if (LOG_THREADS) {
Log.i("GLThread", "surfaceDestroyed tid=" + getId());
}
mHasSurface = false;
sGLThreadManager.notifyAll();
while (!mWaitingForSurface && isAlive() && !mDone) {
try {
sGLThreadManager.wait();
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
}
}

public void onPause() {
synchronized (sGLThreadManager) {
mPaused = true;
sGLThreadManager.notifyAll();
}
}

public void onResume() {
synchronized (sGLThreadManager) {
mPaused = false;
mRequestRender = true;
sGLThreadManager.notifyAll();
}
}

public void onWindowResize(int w, int h) {
synchronized (sGLThreadManager) {
mWidth = w;
mHeight = h;
mSizeChanged = true;
sGLThreadManager.notifyAll();
}
}

public void requestExitAndWait() {
// don't call this from GLThread thread or it is a guaranteed
// deadlock!
synchronized (sGLThreadManager) {
mDone = true;
sGLThreadManager.notifyAll();
}
try {
join();
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
}

/**
* Queue an "event" to be run on the GL rendering thread.
*
* @param r
* the runnable to be run on the GL rendering thread.
*/
public void queueEvent(Runnable r) {
synchronized (this) {
mEventQueue.add(r);
synchronized (sGLThreadManager) {
mEventsWaiting = true;
sGLThreadManager.notifyAll();
}
}
}

private Runnable getEvent() {
synchronized (this) {
if (mEventQueue.size() > 0) {
return mEventQueue.remove(0);
}

}
return null;
}

private class GLThreadManager {

public synchronized void threadExiting(GLThread thread) {
if (LOG_THREADS) {
Log.i("GLThread", "exiting tid=" + thread.getId());
}
thread.mDone = true;
if (mEglOwner == thread) {
mEglOwner = null;
}
notifyAll();
}

/*
* Tries once to acquire the right to use an EGL surface. Does not block.
*
* @return true if the right to use an EGL surface was acquired.
*/
public synchronized boolean tryAcquireEglSurface(GLThread thread) {
if (mEglOwner == thread || mEglOwner == null) {
mEglOwner = thread;
notifyAll();
return true;
}
return false;
}

public synchronized void releaseEglSurface(GLThread thread) {
if (mEglOwner == thread) {
mEglOwner = null;
}
notifyAll();
}
}
}

interface EGLConfigChooser {
EGLConfig chooseConfig(EGL10 egl, EGLDisplay display);
}

abstract class BaseConfigChooser implements EGLConfigChooser {
public BaseConfigChooser(int[] configSpec) {
mConfigSpec = configSpec;
}

public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {
int[] num_config = new int[1];
egl.eglChooseConfig(display, mConfigSpec, null, 0, num_config);

int numConfigs = num_config[0];

if (numConfigs <= 0) {
throw new IllegalArgumentException("No configs match configSpec");
}

EGLConfig[] configs = new EGLConfig[numConfigs];
egl.eglChooseConfig(display, mConfigSpec, configs, numConfigs, num_config);
EGLConfig config = chooseConfig(egl, display, configs);
if (config == null) {
throw new IllegalArgumentException("No config chosen");
}
return config;
}

abstract EGLConfig chooseConfig(EGL10 egl, EGLDisplay display, EGLConfig[] configs);

protected int[] mConfigSpec;
public static class ComponentSizeChooser extends BaseConfigChooser {
public ComponentSizeChooser(int redSize, int greenSize, int blueSize, int alphaSize, int depthSize,
int stencilSize) {
super(new int[] { EGL10.EGL_RED_SIZE, redSize, EGL10.EGL_GREEN_SIZE, greenSize, EGL10.EGL_BLUE_SIZE,
blueSize, EGL10.EGL_ALPHA_SIZE, alphaSize, EGL10.EGL_DEPTH_SIZE, depthSize, EGL10.EGL_STENCIL_SIZE,
stencilSize, EGL10.EGL_NONE });
mValue = new int[1];
mRedSize = redSize;
mGreenSize = greenSize;
mBlueSize = blueSize;
mAlphaSize = alphaSize;
mDepthSize = depthSize;
mStencilSize = stencilSize;
}

@Override
public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display, EGLConfig[] configs) {
EGLConfig closestConfig = null;
int closestDistance = 1000;
for (EGLConfig config : configs) {
int d = findConfigAttrib(egl, display, config, EGL10.EGL_DEPTH_SIZE, 0);
int s = findConfigAttrib(egl, display, config, EGL10.EGL_STENCIL_SIZE, 0);
if (d >= mDepthSize && s >= mStencilSize) {
int r = findConfigAttrib(egl, display, config, EGL10.EGL_RED_SIZE, 0);
int g = findConfigAttrib(egl, display, config, EGL10.EGL_GREEN_SIZE, 0);
int b = findConfigAttrib(egl, display, config, EGL10.EGL_BLUE_SIZE, 0);
int a = findConfigAttrib(egl, display, config, EGL10.EGL_ALPHA_SIZE, 0);
int distance = Math.abs(r - mRedSize) + Math.abs(g - mGreenSize) + Math.abs(b - mBlueSize)
+ Math.abs(a - mAlphaSize);
if (distance < closestDistance) {
closestDistance = distance;
closestConfig = config;
}
}
}
return closestConfig;
}

private int findConfigAttrib(EGL10 egl, EGLDisplay display, EGLConfig config, int attribute, int defaultValue) {

if (egl.eglGetConfigAttrib(display, config, attribute, mValue)) {
return mValue[0];
}
return defaultValue;
}

private int[] mValue;
// Subclasses can adjust these values:
protected int mRedSize;
protected int mGreenSize;
protected int mBlueSize;
protected int mAlphaSize;
protected int mDepthSize;
protected int mStencilSize;
}

/**
* This class will choose a supported surface as close to RGB565 as possible, with or without a depth buffer.
*
*/
public static class SimpleEGLConfigChooser extends ComponentSizeChooser {
public SimpleEGLConfigChooser(boolean withDepthBuffer) {
super(4, 4, 4, 0, withDepthBuffer ? 16 : 0, 0);
// Adjust target values. This way we'll accept a 4444 or
// 555 buffer if there's no 565 buffer available.
mRedSize = 5;
mGreenSize = 6;
mBlueSize = 5;
}
}
}

public class MyWallpaperService extends GLWallpaperService {
public MyWallpaperService() {
super();
}

public Engine onCreateEngine() {
MyEngine engine = new MyEngine();
return engine;
}

// prefs and sensor interface is optional, just showing that this is where you do all of that - everything that would normally be in an activity is in here.
class MyEngine extends GLEngine implements SharedPreferences.OnSharedPreferenceChangeListener, SensorEventListener {
MyRenderer renderer;
public MyEngine() {
super();
// handle prefs, other initialization
renderer = new MyRenderer();
setRenderer(renderer);
setRenderMode(RENDERMODE_WHEN_DIRTY);
}

public void onDestroy() {
super.onDestroy();
if (renderer != null) {
renderer.release(); // assuming yours has this method - it should!
}
renderer = null;
}